Author Topic: Re: 4: Switches/Bypass/Etc....  (Read 5635 times)

GroovyMan

Re: 4: Switches/Bypass/Etc....
« on: December 09, 2009, 02:34:47 PM »
I'm not sure this is the right place for this question but  anyway,

It struck me that 3PDT switches are quite expensive and I wondered if you could use a SPST switch with a DPDT relay instead. You could put the LED in series with the coil of the relay so that the LED came on when the coil was energised by the footswitch. The switching poles of the relay would then be used to switch in the circuit or bypass.

This seems a like a much cheaper option and would quite simple to implement? Is there any reason why this wouldn't work?

Thanks,
Ben
Next project: Ross Compressor
Completed: NPN Boost, Vox V847 True Bypass and DC socke mods.

aron

Re: Re: 4: Switches/Bypass/Etc....
« Reply #1 on: December 09, 2009, 05:07:07 PM »
We used to use the millenium bypass and other options, but the 3PDT is simple, it's not that expensive and it works. An SPST that handles a foot stomp is not that much cheaper. Add in the relay and I would think it would be around the same price or more.

aron


aron


GroovyMan

Re: 4: Switches/Bypass/Etc....
« Reply #4 on: January 02, 2010, 09:35:35 AM »
Thanks for the links Aron,

For those who don't want to trawl through the text, the main problem here is going to be the coil current will drain the battery pretty quickly. If you're going to do it then CMOS multiplexer would be a better choice and then you only need a SPST switch.. which would be much cheaper.

Ben
Next project: Ross Compressor
Completed: NPN Boost, Vox V847 True Bypass and DC socke mods.

composition4

Re: 4: Switches/Bypass/Etc....
« Reply #5 on: January 03, 2010, 04:09:49 AM »
Coil current is negligible if you use a latching relay, as the pulse of current only needs to be in the order of 10 - 50ms for the relay to flip over.

Jonathan

GroovyMan

Re: 4: Switches/Bypass/Etc....
« Reply #6 on: January 03, 2010, 06:41:17 AM »
Right, but my plan was to put the LED in series with the coil. With a latching relay I guess the LED would only come on during the pulse?
Next project: Ross Compressor
Completed: NPN Boost, Vox V847 True Bypass and DC socke mods.

composition4

Re: 4: Switches/Bypass/Etc....
« Reply #7 on: January 04, 2010, 12:49:56 AM »
Use R.G.'s millenium bypass for the LED.. that way you can use SPST momentary footswitch + DPDT relay, and still have true bypass + LED

Jonathan